The pollution caused by rocket launches
Rocket launches are an integral part of our 21st-Century world. But how do we stop their polluting exhausts accelerating climate change?
The Kazakh Steppe is a vast area of grassland that stretches from northern Kazakhstan into Russia. It is home to the world's oldest spaceport, the Baikonur Cosmodrome. From its launchpads, both the world's first artificial satellite and the first human spaceflight, Sputnik 1 and Vostok 1, were launched.
The fuel used by many of the rockets that blasted off from Baikonur was UDMH (unsymmetrical dimethylhydrazine), a very useful propellant for the pioneering Soviet scientists. UDMH didn't need a source of ignition. It could be stored at room temperature, and it released a lot of energy. Yet it came to be dubbed "devil's venom" by the scientists who used it.
Devil's venom was highly carcinogenic to humans and it's blamed for turning a large area of the steppe into an ecological disaster zone. It's reported that UDMH rained down on the grasslands when it spilled out of the used first and second stages of Proton rockets and poisoned the soil for decades to come.
In television, and film, spaceflight is usually represented as having little or no impact on the environment. Yet it should be obvious that rocket engines spew out pollution into the atmosphere, like any form of combustion-driven propulsion.
Perhaps the black carbon, or soot, and other emissions didn't matter when only around 70 commercial rocket launches a year took place. Now that number has doubled; it is expected to increase significantly more over the next two decades due to the growth in demand for services like satellite internet services and space tourism.
You might also like:
- The giant rocket launcher in the jungle
- Britain’s plans for Nazi spaceships
- Inside Nasa’s giant rocket lab
At least three scientific research papers have already been published this year on the impact of rocket emissions on the atmosphere, temperatures, and the ozone layer. Some scientists are worried that these carbon particles can act like a form of geo-engineering by absorbing heat.
"We have been aware of it for a fair amount of time, but there haven't been a lot of studies," says Christopher Maloney, a research scientist at the NOAA Chemical Sciences Laboratory, who is the co-author of one of the papers. "There are studies that go back to the early 2000s, and even a few beforehand, but it's never been that big of a concern or focus because the number of rockets being launched every year was so small. Now if you look at the trajectory of the industry, or proposals from various governments, then we can expect to see a tenfold increase in rocket launches and emissions within the next 10 to 20 years, and that is why, suddenly, it's starting to get momentum in terms of scientific research."
The Baikonur launch site in Kazakhstan has created a large zone of pollution thanks to vast amounts of toxic rocket fuel seeping into soil (Credit: Bill Ingalls/Nasa)
There is also a great deal of uncertainty as to the effects of rocket emissions on the atmosphere. Despite the work of pioneering scientists like Martin Ross, there has been little momentum to study the impact of space travel emissions on the atmosphere until recently because rocket launches were infrequent, the amount of emissions were low and it wasn't seen as a major contributing factor to climate change.
The pollution caused by rocket emissions can also seem insignificant compared to the other challenges the world faces, and the benefits the space industry brings to a 21st-Century world. Indeed, the percentage of fossil fuels burned by the space industry is only about 1% of that burned by conventional aviation.
When we compare the amount emitted from rocket launches to aircraft, it doesn't sound like a lot – Eloise Marais
"Last year's number of missions was 144 worldwide," says William Pomerantz, vice president of special projects at Virgin Orbit, which launches small satellites horizontally from under the wing of a Boeing 747. Their rocket uses about 1/20th of the fuel of typical ground-launched, heavy-lift rockets, and recent launches include satellites now playing a key role in the collection of climate data. "Given this volume, the space launch industry remains a relatively small driver of atmospheric emissions compared with say, commercial aviation with more than 20 million flights worldwide, and other industries."
Eloise Marais, an associate professor in physical geography at University College London, and co-author of one of the recent research papers, thinks this comparison is "erroneous".
"When we compare the amount emitted from rocket launches to aircraft, it doesn't sound like a lot," she says. "But this comparison was always erroneous because aircraft released their pollutants within the troposphere and the lower stratosphere, whereas rockets are releasing their pollutants all the way from the surface of the Earth to the mesophere, and when pollution is released into those upper layers it lasts for a longer time than earthbound sources."
The studies published so far by researchers such as Maloney and Marais tend to focus on Rocket Propellant-1, or RP-1, because this highly refined form of kerosene is one of the most popular rocket fuels. It helped blast iconic rockets such as the Saturn, Delta, Atlas, and Soyuz and, in the 21st Century, SpaceX's Falcon 9 and Virgin Orbit's horizontally launched rocket, into space. RP-1 is popular because it is cheaper, stable at room temperature and isn't dangerously explosive. It also packs a lot of punch.
Last year there were more than 140 rocket launches around the world - but this is likely to grow substantially (Credit: Korea Aerospace Research Institute/Getty Images)
Marais and a team of researchers from University College London (UCL), the University of Cambridge and Massachusetts Institute of Technology (MIT) used a 3D model to explore the impact on the atmosphere of rocket launches and re-entry in 2019, and the future impact of space tourism promoted by companies like Virgin Galactic and Blue Origin.
Marais's team found that black carbon emissions will more than double after just an additional three years of space tourism launches, and that particles emitted by rockets are almost 500 times more efficient at holding heat in the atmosphere than all other sources of soot combined, resulting in an enhanced warming climate effect. While current loss of ozone due to space launches is small, the impact of space tourism launches may undermine the recovery in the ozone layer experienced after the success of the 1987 Montreal Protocol which banned substances that deplete the Earth's ozone layer.
When you have the cumulative effect of more launches, it is going to get interesting – Dimitris Drikakis
Maloney and his team calculated that each year rocket launches that use RP-1 collectively expel around 1 gigagram, or 1,000 metric tons, of black carbon into the stratosphere. Thanks to the growing number of rockets launched, this could reach 10 gigagrams a year in a couple of decades, along with a temperature rise in parts of the stratosphere of as much as 1.5 degrees Celsius, and a thinning of the ozone layer. If the amount of black carbon expelled into the atmosphere reach 30 gigagrams a year, or even 100, then there will be some cooling of the surface of the planet under this black carbon umbrella.
For their research paper, Ioannis Kokkinakis and Dimitris Drikakis, scientists at the University of Nicosia in Cyprus, used real rocket launch data from a Space X Falcon 9 rocket in 2016 to create the "first high-resolution and high-order computational model" of its kind to analyse in detail the impact of rocket emissions on the climate. This Space X launch was chosen because useful webcam footage of the exhaust gases was available. One of the "biggest surprises" they found is that in the first stage of the rocket launch around 116 tons of CO2 was emitted in 165 seconds. "That is quite significant," says Drikakis. "Yes, we don't know the actual impact on the atmosphere because atmospheric chemistry is a very complicated matter, but when you have the cumulative effect of more launches, it is going to get interesting."
Orbex plan to launch rockets up to 12 times a year (Credit: Orbex)
Another discovery was that nitrogen oxides were formed from the heating of the atmospheric air by the hot rocket exhaust gases, and their impact at lower altitudes seems to depend on the design of the rocket nozzles. "This is important because rocket design can potentially mitigate this effect," Drikakis says.
Every model makes assumptions for efficiency and due to the complex nature of the Earth's atmosphere, and then undergoes rigorous validation. "If they're all converging on a single story, then you can have fairly good confidence that they are on to something," says Maloney.
Now there is a race on to develop alternatives to existing fuels like RP-1 and UDMH, and liquid methane appears to be in the lead. Several new rocket engines, including SpaceX's Raptor and the European Space Agency's Prometheus engine, have been designed to use this gas as a fuel because it has a higher performance than other fuels, meaning the rocket can be smaller and produce less soot when it's launched. Its lower cost means the price of a rocket launch can be reduced, too.
Several rocket start-ups are at a relatively early stage of experimenting with sustainable alternatives to RP-1 made from waste plastic or biomass
Methane, however, is controversial because it is one of the worst gases as far as global warming is concerned. It is around 80 times more warming than carbon dioxide over its lifetime.
Several rocket start-ups are at a relatively early stage of experimenting with sustainable alternatives to RP-1 made from waste plastic or biomass. Such start-ups typically focus on the easier tasks of reducing their carbon footprint and protecting the environment around the space port, as well as the harder job of cutting emissions in the stratosphere.
Orbex is a UK-based low-cost launch company with a rocket factory in Forres, near Inverness in Scotland. Orbex plans to launch its small rocket called Prime up to 12 times a year from Space Hub Sutherland in the far north of the country.
Launching rockets from air, as Virigin Orbit has been experimenting with, could be one alternative to conventional launches (Credit: Virgin Orbital)
The fuel its rocket runs on is bio-propane, a renewable biofuel created as a waste product from the production of biodiesel. Orbex's rocket could end up with around 90% fewer emissions than an RP-1-fuelled launch. It should also produce less soot than rockets burning its kerosene cousin.
Virgin Orbit is looking into the use of sustainable rocket fuels.
The other option to reduce the industry's atmospheric impact is to explore new ways of launching satellites, horizontally like Virgin Orbit, or even in a sling shot, as Nasa is exploring. Like a child's toy, this will work by attaching a rocket payload to the end of a huge arm that will be accelerated by electric motors to very high speeds, flinging the rocket out into space.
People are starting to wake up to the disproportionate impact on the atmosphere of the space launch industry, but nothing happens in a hurry in space – Chris Larmour
Researchers fear that the space industry has little incentive to change because of the absence of regulations, a reluctance to abandon safe and proven technology, and the fact that new propellants mean expensive new engines and lengthy testing.
"People are starting to wake up to the disproportionate impact on the atmosphere of the space launch industry, but nothing happens in a hurry in space," says Chris Larmour, co-founder and CEO of Orbex. "I definitely think we'll see regulation coming in. The government will set an emissions target and we will have to adhere to it. The industry can lobby all they want, but in the end, it's the politicians that make laws."
Yet, others are weary of a regulatory solution to a complex problem.
"One-size-fits-all solutions are very challenging given the broad range of technology types," says Pomerantz. "However, technology innovation will be key. Propulsion technology is one part of that, but what is really needed is a holistic view of how we maximise the efficiency of full systems – what kind of spacecraft we build, what jobs they do, and how they get launched."
Join one million Future fans by liking us onFacebook, or follow us onTwitterorInstagram.
If you liked this story,sign up for the weekly bbc.com features newsletter, called "The Essential List" – a handpicked selection of stories from
BBCFuture,Culture,Worklife,TravelandReeldelivered to your inbox every Friday.
How much pollution do rocket launches cause? ›
Maloney and his team calculated that each year rocket launches that use RP-1 collectively expel around 1 gigagram, or 1,000 metric tons, of black carbon into the stratosphere.Do rocket ships cause pollution? ›
Such rockets generate exhaust that contains carbon dioxide and water vapor, as well as varying amounts of soot, nitrous oxides, and sulfur. Carbon dioxide, water vapor, and nitrous oxides are all greenhouse gases that absorb heat and warm our planet.What are the effects of a rocket launch? ›
Currently, rockets inject about 1,000 tons of soot per year into the otherwise pristine upper layers of Earth's atmosphere. This pollutant accumulates at high altitudes over the years and absorbs heat, which can lead to the warming of those atmospheric layers.How does rocket fuel affect the environment? ›
While any carbon-based fuel produces black carbon, kerosene is a particularly bad offender, and only rockets deposit black carbon high in the atmosphere. Previous work has shown that black carbon can remain in the stratosphere for up to five years, trapping heat from the sun and potentially damaging the ozone layer.What are the types of pollution? ›
The three major types of pollution are air pollution, water pollution, and land pollution.What is pollution explain? ›
Pollution occurs when an amount of any substance or any form of energy is put into the environment at a rate faster than it can be dispersed or safely stored. The term pollution can refer to both artificial and natural materials that are created, consumed, and discarded in an unsustainable manner.What gases do rockets produce? ›
The Nature of Rocket Emissions
The most common gaseous emissions are water vapor and carbon dioxide from liquid and solid fuels, as well as hydrochloric acid from only solid fuels.
The 135 successful orbital launches in 2021 don't include 11 failed orbital launch attempts. The previous record for the most successful orbital launches in a year was 129, set in 1984. But declining post-Cold War military budgets led to lower launch rates in the 1990s and 2000s.How much fuel is burned at a rocket launch? ›
At liftoff, the two Solid Rocket Boosters consume 11,000 pounds of fuel per second. That's two million times the rate at which fuel is burned by the average family car. The twin Solid Rocket Boosters generate a combined thrust of 5.3 million pounds.Do rockets harm the atmosphere? ›
The study also found that rockets deplete the Earth's atmospheric ozone layer, which protects the planet from harmful ultraviolet radiation from the sun. Rockets that burn solid, chlorine-based fuels harm ozone by releasing chlorine, which destroys ozone, directly into the stratosphere.
Is space travel pollution? ›
Launch rates have tripled
Rockets are the only direct source of human-produced aerosol pollution above the troposphere, the lowest region of the atmosphere, which extends to a height of about 5 to 10 miles above the Earth's surface.
Rocket launches affect Earth's ozone layer
But a NOAA study suggests that a significant boost in spaceflight activity might damage the protective ozone layer on the one planet where we live. Kerosene-burning rocket engines widely used by the global launch industry emit exhaust containing black carbon, or soot.
|Characteristic||Emissions in billion metric tons|
These byproducts of space travel can also contribute to ozone depletion and climate change through the deposition of aluminum compounds and black carbon.How much does a rocket launch cost? ›
A Falcon 9 launch will cost $67 million, up from $62 million, and a Falcon Heavy launch will now run $97 million, up from $90 million. A footnote on SpaceX's pricing page notes that “missions purchased in 2022 but flown beyond 2023 may be subject to additional adjustments due to inflation.”Why is pollution a problem? ›
Pollution stunts economic growth, exacerbates poverty and inequality in both urban and rural areas and significantly contributes to climate change. Poor people, who cannot afford to protect themselves from the negative impacts of pollution, end up suffering the most.What does pollution mean in 250 words? ›
Pollution is the process of making the environment land water and air dirty by adding harmful substances to it. Pollution causes imbalance in the environment. This imbalance has threatened the very survival of all forms of life. It is a threat to the whole world.How does pollution affect us? ›
It increases the risk of respiratory infections, heart disease and lung cancer. Both short and long term exposure to air pollutants have been associated with health impacts. More severe impacts affect people who are already ill. Children, the elderly and poor people are more susceptible.How do we control pollution? ›
- Reduce the number of trips you take in your car.
- Reduce or eliminate fireplace and wood stove use.
- Avoid burning leaves, trash, and other materials.
- Avoid using gas-powered lawn and garden equipment.
- Using public transports. ...
- Turn off the lights when not in use. ...
- Recycle and Reuse. ...
- No to plastic bags. ...
- Reduction of forest fires and smoking. ...
- Use of fans instead of Air Conditioner. ...
- Use filters for chimneys. ...
- Avoid usage of crackers.
Do rockets damage the ozone layer? ›
A recent report published by the National Oceanic and Atmospheric Administration (NOAA) found that space travel could be damaging the protective layer of our atmosphere: the ozone layer. According to the report, kerosene-burning rocket engines emit black carbon into the stratosphere, where a layer of ozone exists.How much air pollution is caused by space travel? ›
The research team used a climate model to simulate the impact of approximately 10,000 metric tons of soot pollution injected into the stratosphere over the northern hemisphere every year for 50 years. Currently, an estimated 1,000 tons of rocket soot exhaust are emitted annually.How much fuel is burned at a rocket launch? ›
At liftoff, the two Solid Rocket Boosters consume 11,000 pounds of fuel per second. That's two million times the rate at which fuel is burned by the average family car. The twin Solid Rocket Boosters generate a combined thrust of 5.3 million pounds.Do rockets poke holes in the ozone? ›
Rockets don't leave holes behind them any more than cars do. The air closes immediately behind them and the pollutants drift away quickly. There aren't that many rockets. Most of the pollutants in the ozone layer drift up from the surface.